This paper studies the electromechanical model of a jigsaw mechanism. The jigsaw is powered by a battery, which drives a DC motor. The rotational motion is converted into linear motion through a Scotch Yoke mechanism. The electromechanical equations are based on energy approach using the Lagrange-equation. The Lagrange function contains the energies of the model, i.e., the kinetic co-energy of the kinematic chain and the magnetic co-energy of the inductance. As regard the non-conservative elements their virtual works are written. The formulated equations of the jigsaw model allow us to examine this force-energy relationship.

The aim of this paper was to reduce the current spikes in battery-powered saw motors by designing and implementing a sliding mode model-following adaptive controller. The proposed controller reduces overcurrent consumption, improves system energy efficiency, and effectively maximizes battery runtime, especially under high-load conditions. By applying nonlinear compensation techniques, the controller can ensure smooth motor operation, reduce mechanical stress, and prolong tool life. The results showed that this control strategy is particularly suitable for hand tools, where a long battery life is essential for efficient operation.

In this paper, the construction and operation of a measuring bench for measur-ing the vibration state of a rotating shaft and the evaluation of the measurement results are presented. The design of the measuring bench was aimed at measuring the vibration gen-erated by the excitation effects on the shaft. The effect of the imbalance and the position of the disc on the vibration characteristics is shown in diagrams. It is also observed that at higher speeds the vibration plotted shows an irregular shape. This is due to the excitation effects on the whole structure.

A forgó mozgást végző tengelyek, gépelemek egyik működés közbeni fontos jellemzője a kritikus fordulatszám, mely a forgó mozgást végző összeállítás sajátfrekvenciájával függ össze. A valóságban a tengely rugalmas elem, amelyre, ha egy kiegyensúlyozatlan forgórészt szerelnek, a szögsebesség négyzetével és az excentricitással arányos centrifugális erő hat. Az ehhez köthető gerjesztő hatások káros rezgésekhez vezethet. A kritikus fordulatszámon a forgórész nyugtalanul viselkedik, a gép rezgéseinek amplitúdója megnövekszik. Tervezésnél gondoskodni kell arról, hogy a kritikus fordulatszámon a gép tartósan ne üzemelhessen. Az ilyen rendszerek kritikus fordulatszámának meghatározására léteznek mechanikai modellek, azonban pontosabb képet kapunk a valós tengely forgás közben fellépő rezonanciájának mérésével. A cikk egy ilyen mérőpadon végzett mérési eredményeket foglalja össze.

This paper studies the electromechanical model of a jigsaw mechanism. The jigsaw is powered by a battery, which drives a DC motor. The rotational motion is converted into linear motion through a Scotch Yoke mechanism. The electromechanical equations are based on energy approach using the Lagrange-equation. The Lagrange function contains the energies of the model, i.e., the kinetic co-energy of the kinematic chain and the magnetic co-energy of the inductance. As regard the non-conservative elements their virtual works are written. The formulated equations of the jigsaw model allow us to examine this force-energy relationship.